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1995 K2500 with 5L 305 Automatic 4x4 - Won't start, suspect ECM

So hopefully this is the right spot to ask this question. Here is the situation, we have a '95 K2500 with a 5L motor and automatic I believe it should be a 4L80e? Anyway been running great for years, then one day after taking it up to the house it won't start. So we did some obvious troubleshooting

a) Checked to hear fuel pump, we hear it
b) Checked fuel pressure at engine, 15psi and pump/filter was changed recently
c) pour some fuel down the throat and it fires right up and runs.
d) Checked wiring around ignition control module, and various grounds
e) added more grounds to block and body just in case

Still nothing. Because it runs when we pour fuel down the throat that kindof suggests ignition/spark etc is all working fine, just the injectors are not spraying fuel for some reason. We swapped the ignition control module from a parts truck anyway since i believe it sends the signal to the computer to tell it to pulse the injectors? Maybe? Not totally sure but either way no change with the replaced ICM. While I wasn't around, my father-in-law took the ECM from the parts truck which I believe is a 1994 C1500 with 5.7L Automatic so a completely different drivetrain and put it in the 5.0L 4x4 and tried to start it, it backfired pretty bad. Anyway to me that's a bit of a clue, a backfire would suggest the injectors were firing and it had way too much fuel... not sure what the fuel mapping is like between a 5L and 5.7L but even whatever put the old ECM back in and again nothing happens.

So... I'm beginning to suspect the ECM is having issues for whatever reason, I took it out and looked and it's a 16197427 with the part number BJXL

I went to the wreckers and of course they have nothing with a 5L in it, closest I could find is a 16197427 with BJYL which I believe is a 1995 5.7L K1500 automatic... so close but wrong engine size.

So my question is, can I take a wreckers 16197427 with the BJYL EPROM and reprogram it to be a BJXL? And if so... how? And where could I find a .bin for a BJXL so far I haven't been able to find one anywhere for downloading.

OR... if anyone has any suggestions to try I'm all ears! Maybe it's not the ECM at all but I'm stumped why those injectors are not firing

It would be best to have matching BJXL, but for trouble shooting purposes the BJYL will work. The BJYL will help identify if the computer or Memcal is the no start problem, nothing else. I would first try the wreckers 16197427 with the BJXL to see if the engine starts, if the engine starts then problem solved (bad computer).

Thanks for the reply guys!I didn't think about swapping the memcal out of the '95 and into the 16197427 from the other truck, unfortunately the parts truck is a fair distance away so no longer an option since we took the ECM back to the other truck. But I called around a couple wreckers, and did find one who has some 16197427 that came from trucks that had the 305 engine, he couldn't find one that had the BJXL program (it seems to be a bit of a unicorn... can't find the .bin and can't find any information on it at all or any for sale even!) I think he said one of the ones he had was a BJHL?But either way, could using this work in this truck? I mean, what all is programmed into these memcals? If this one is out of a half tonne, I'm guessing it'll have the 4L60 and since ours is a 3/4 tonne guessing it'll have the 4L80? Does that matter much or would the truck still be able to drive just with different shift points? If the gear ratio is wrong, will all it affect is the speedometer?Basically, if I pick up this 16197427 that came out of a truck with a 305 and put it into our '95 truck with it's 305 and it starts up... first thing I'd do is remove the memcal from the old 16197427 and plug it in to see if it'll work maybe the 16197427 is simply bad. But if it doesn't, and the BJHL memcal works but the stock BJXL doesn't... until I can hunt down a replacement memcal or find someone who can reprogram the wrecker one to match the BJXL can I still drive the truck or would it be bad?

It's been a few days since you've posted this, so you may have already figured it out. I'd bet that you have a 4L60 and not the '80. BJXL is for a 4L60 and I don't recall seeing an '80 behind a 5.0 (though for some strange reason they did come behind a 4.3). I couldn't find a BJHL, so that might not be the right code. Try swapping your MEMCAL into another ECM and see what happens.